a soldering problem? I think maybe not, you have soldered before and it isn't hard to do. it wouldn't harm it to run the solder over the pins again.
I'm at a loss as to why you are having issues.
You could try and power off the GSM module to see if it makes a difference.
echo -e "AT+CPWROFF\r\n" > /dev/ttyACM0
Have you tried assisted GPS? and see if it maintains a fix?
You could also try to use U-Center to get more verbose information to help with troubleshooting.
We may have to send you a new one.
I still see 3 on Amazon.com
Amazon is USD and OzzMaker.com is AUD. After conversation, Amazon is more expensive. This is because Amazon charges a lot of fees. But the benefit is that you get it a lot quicker.
We were working on a LTE version.. but that has been put on hold because of COVID-19. We will start on it again soon.
Mark --OzzMaker.com --